1. Field of the Invention
This invention relates to the field of electrical connectors, and in particular to a Universal Serial Bus (USB) connector with a built-in or integral over-current protection device such as a fuse. The invention also relates to a Universal Serial Bus connector with a built-in or integral over-current indicator.
2. Description of Related Art
The Universal Serial Bus connector is a recently developed connector that is designed to replace all the various input/output interfaces currently used on personal computers, providing a single interface for all peripherals. The Universal Serial Bus specifications support hot pluggability, permitting peripherals to be connected and disconnected to a computer system without having to shut down the system, and includes such features as polarization and power contact positions. In addition, the specifications call for the inclusion of a resettable fuse on the interface card to protect the system from over-currents.
Placement of a fuse on the interface card fulfills the need for system protection, but makes the fuse difficult to access, and thus when an over-current condition does occur and the connection is broken, it is difficult for a user to diagnose the reason why data is not being transferred, causing the user to waste time checking aspects of the system that are not at fault.
The present invention seeks to provide a Universal Serial Bus interface in which the over-current protection device is integrated in a practical manner into the bus connector rather than provided on the interface card. In addition to the usual advantages of integrating components, i.e., space savings on the circuit board and convenience, integration of the over-current protection device into the connector has the advantage of enabling the source of a data or power transmission failure to be more readily traced because the device can then be connected to an indicator light placed at the front of the connector where it is visible to a user without having to open the computer system and examine the card itself.
It has previously been proposed to place an over-current protection device such as a resettable fuse in a Universal Serial Bus connector by including a printed circuit board within the connector, and soldering the over-current protection device to the printed circuit board. However, inclusion of a printed circuit board in the small space available in the Universal Serial Bus connector and other similar high speed data connectors is inconvenient and significantly increases the difficulty and costs of assembling the connector.
It has also previously been proposed to include indicator lights within the housing of electrical connectors. However, none of the prior electrical connector indicator lights is arranged to provide an indication of the condition of a component within the connector itself. Instead, the indicator lights of the prior connectors are arranged to have leads extending to the circuit board for indicating the presence or absence of a signal in the signal lines. In contrast, an over-current condition that causes a fuse to open can only be detected by shunt connecting the indicator to the protection device so that the presence of a current on the input line to the connector will cause the indicator light to illuminate when the fuse is in an open circuit condition.
Because of the difficulties in placing an in-line component in a data bus connector, and despite the potential for space savings on the circuit board and more convenient assembly, there has been little motivation to attempt such placement. However, if there were a way to fit an in-line component into a data bus connector, such as the Universal Serial Bus connector, in a relatively simple manner, then the advantages of space savings and convenience would begin to outweigh the difficulties. Add the possibility of providing an indication of line problems and the resulting connector would represent a significant improvement over existing Universal Serial Bus connectors.